The major objective of this project is to identify the cellular and biochemical factors associated with the development of benign prostatic hyperplasia (BPH). Three approaches will be taken. First, according to the work of McNeal, BPH appears to selectively involve the transition zone (TZ) of the human prostate. We postulate that there will be intrinsic phenotyping differences within subpopulations of stromal (S) and epithelial (E) cells from the TZ compared with S/E cells from other parts of the prostate. To test this hypothesis, we propose to conduct immunohistochemical studies on serial sections of whole human prostates collected either from organ donors or from fresh autopsy specimens. Central (CZ), peripheral (PZ), and TZ of the prostate will be identified according to McNeal's description. The presence of androgen receptors, epidermal growth factor, and basic fibroblast growth factor will be assessed from both frozen tissues and dissociated cells, in an attempt to establish a zonal variation in distribution of these marker proteins within the prostate. The second approach deals with tissue culture of S and E cells of the human prostate. Our previous studies have demonstrated the importance of S-E cell interaction in the human prostate which may involve the elaboration of growth factors which, in turn, impact on the respective target cells. We propose to fractionate conditioned medium collected from cultures of S cells and E cells of the prostate. Attempts will be made to identify the specific growth factors in the fractions that show biological activity in terms of proliferation and differentiation. Attempts will be made to isolate secretory cells (SC) from basal cells (BC) in the epithelial fraction and smooth muscle cells (SMC) from fibroblasts (FB) in the stromal fraction of the human prostate. The biological activity of these cell types and their respective natural extracellular matrix will be studied separately in an attempt to deduce the cellular and biochemical factors of BPH development. Finally, we postulate that, aside from the intrinsic stromal-epithelial interaction, prostatic growth can be affected by extrinsic factors such as neurotransmitters (see Project 3) and non- androgenic testicular factors (see Project 2). These substances will be tested directly in the present culture systems using E and S subpopulations as targets.